Many historical bridges named London Bridge have spanned the River Thames between the City of London and Southwark, in central London. The current crossing, which opened to traffic in 1974, is a box girder bridge built from concrete and steel. This replaced a 19th-century stone-arched bridge, which in turn superseded a 600-year-old medieval structure. This was preceded by a succession of timber bridges, the first built by the Roman founders of London.[1]

The abutments of modern London Bridge rest several metres above natural embankments of gravel, sand and clay. From the late Neolithic era the southern embankment formed a natural causeway above the surrounding swamp and marsh of the river's estuary; the northern ascended to higher ground at the present site of Cornhill. Between the embankments, the River Thames could have been crossed by ford when the tide was low, or ferry when it was high. Both embankments, particularly the northern, would have offered stable backheads for boat traffic up and downstream – the Thames and its estuary were a major inland and Continental trade route from at least the 9th century BC.[4] There is archaeological evidence for scattered Neolithic, Bronze Age and Iron Age settlement nearby, but until a bridge was built there, London did not exist.[5] Two ancient fords were in use a few miles upstream, beyond the river's upper tidal reach. They were aligned with the course of Watling Street and led into the heartlands of the Catuvellauni, who at the time of Caesar's invasion of 54 BC were Britain's most powerful tribe. Some time before Claudius' conquest of AD 43, power shifted to the Trinovantes, who held the region northeast of the Thames estuary from a capital at Camulodunum. The first London Bridge was built by the Roman military as part of a road-building programme to help consolidate their conquest.[6]

The first bridge was probably a Roman military pontoon type, giving a rapid overland shortcut to Camulodunum from the southern and Kentish ports, along the Roman roads of Stane Street and Watling Street (now the A2). The Trinovantes submitted to Rome; a major colonia was imposed on Camulodunum, which became capital city of the new Roman province of Britannia. Around AD 55, this temporary bridge was replaced by a permanent timber piled bridge, maintained and guarded by a small garrison. On the relatively high, dry ground at the northern end of the bridge, a small, opportunistic trading and shipping settlement took root, and grew into the town of Londinium.[7] A smaller settlement developed at the southern end of the bridge, in the area now known as Southwark. The bridge was probably destroyed along with the town in the Boudican revolt (60 AD), but both were rebuilt and Londinium became the administrative and mercantile capital of Roman Britain. The upstream fords and ferries remained in use but the bridge offered uninterrupted, mass movement of foot, horse, and wheeled traffic across the Thames, linking four major arterial road systems north of the Thames with four to the south. Just downstream of the bridge were substantial quays and depots, convenient to seagoing trade between Britain and the rest of the Roman Empire.[8][9]

With the end of Roman rule in Britain in the early 5th century, Londinium was gradually abandoned and the bridge fell into disrepair. In the Saxon period, the river became a boundary between the emergent, mutually hostile kingdoms of Mercia and Wessex. By the late 9th century, Danish invasions prompted at least a partial reoccupation of London by the Saxons. The bridge may have been rebuilt by Alfred the Great soon after the Battle of Edington as part of Alfred's redevelopment of London in his system of burhs,[10] or it may have been rebuilt around 990 under the Saxon king Æthelred the Unready to hasten his troop movements against Sweyn Forkbeard, father of Cnut the Great. A skaldic tradition describes the bridge's destruction in 1014 by Æthelred's ally Olaf,[11] to divide the Danish forces who held both the walled City of London and Southwark. The earliest contemporary written reference to a Saxon bridge is c.1016 when chroniclers mention how Cnut's ships bypassed the crossing, during his war to regain the throne from Edmund Ironside.

An engraving by Claes Visscher showing Old London Bridge in 1616, with what is now Southwark Cathedral in the foreground. The spiked heads of executed criminals can be seen above the Southwark gatehouse.

After the murder of his erstwhile friend and later opponent Thomas Becket, Archbishop of Canterbury, the penitent King Henry II commissioned a new stone bridge in place of the old, with a chapel at its centre dedicated to Becket as martyr. The archbishop had been a native Londoner and a popular figure. The Chapel of St Thomas on the Bridge became the official start of pilgrimage to his Canterbury shrine; it was grander than some town parish churches, and had an additional river-level entrance for fishermen and ferrymen. Building work began in 1176, supervised by Peter, a priest and chaplain of St Mary Colechurch.[13] The costs would have been enormous; Henry's attempt to meet them with taxes on wool and sheepskins probably gave rise to a later legend that London Bridge was built on wool packs.[13] It was finished by 1209 during the reign of King John. It had taken 33 years to complete, and John licensed out building plots on the bridge to help recoup the costs; but it was never enough. In 1284, in exchange for loans to the royal purse, the City of London acquired the Charter for its maintenance, based on the duties and toll-rights of the former "Brethren of the Bridge".

The bridge was some 26 feet (8 m) wide, and about 800–900 feet (240–270 m) long, supported by 19 irregularly spaced arches, founded on "starlings" set into the river-bed. It had a drawbridge for the passage of tall ships up-river, and defensive gatehouses at both ends. By 1358, it was already crowded, with 138 shops. At least one two-entranced, multi-seated public latrine overhung the bridge parapets and discharged into the river below; so did an unknown number of private latrines reserved for Bridge householders or shopkeepers and bridge officials. In 1382–83 a new latrine was made (or an old one replaced) at considerable cost, at the northern end of the bridge.[14]

The buildings on London Bridge were a major fire hazard and increased the load on its arches, several of which had to be rebuilt over the centuries. In 1212, perhaps the greatest of the early fires of London broke out on both ends of the bridge simultaneously, trapping many people in the middle. Houses on the bridge were burnt during Wat Tyler's Peasants' Revolt in 1381 and during Jack Cade's rebellion in 1450. A major fire of 1633 that destroyed the northern third of the bridge formed a firebreak that prevented further damage to the bridge during the Great Fire of London (1666).

Detail of Old London Bridge on the 1632 oil painting "View of London Bridge" by Claude de Jongh

By the Tudor era there were some 200 buildings on the bridge. Some stood up to seven storeys high, some overhung the river by seven feet, and some overhung the road, to form a dark tunnel through which all traffic had to pass, including (from 1577) the palatial Nonsuch House. The roadway was just 12 feet (4 m) wide, divided into two lanes, so that in each direction, carts, wagons, coaches and pedestrians shared a passageway six feet wide. When the bridge was congested, crossing it could take up to an hour. Those who could afford the fare might prefer to cross by ferry, but the bridge structure had several undesirable effects on river traffic. The narrow arches and wide pier bases restricted the river's tidal ebb and flow, so that in hard winters, the water upstream of the bridge became more susceptible to freezing and impassable by boat. The flow was further obstructed in the 16th century by waterwheels (designed by Peter Morice) installed under the two north arches to drive water pumps, and under the two south arches to power grain mills; the difference in water levels on the two sides of the bridge could be as much as 6 feet (2 m), producing ferocious rapids between the piers.[15] Only the brave or foolhardy attempted to "shoot the bridge"—steer a boat between the starlings when in flood—and some were drowned in the attempt. The bridge was "for wise men to pass over, and for fools to pass under."[16]

The southern gatehouse became the scene of one of London's most notorious sights — a display of the severed heads of traitors, impaled on pikes[1] and dipped in tar and boiled to preserve them against the elements. The head of William Wallace was the first to appear on the gate, in 1305, starting a tradition that was to continue for another 355 years. Other famous heads on pikes included those of Jack Cade in 1450, Thomas More in 1535, Bishop John Fisher in the same year, and Thomas Cromwell in 1540. In 1598, a German visitor to London, Paul Hentzner, counted over 30 heads on the bridge:[17]

“

On the south is a bridge of stone eight hundred feet in length, of wonderful work; it is supported upon twenty piers of square stone, sixty feet high and thirty broad, joined by arches of about twenty feet diameter. The whole is covered on each side with houses so disposed as to have the appearance of a continued street, not at all of a bridge. Upon this is built a tower, on whose top the heads of such as have been executed for high treason are placed on iron spikes: we counted above thirty.

By 1722 congestion was becoming so serious that the Lord Mayor decreed that "all carts, coaches and other carriages coming out of Southwark into this City do keep all along the west side of the said bridge: and all carts and coaches going out of the City do keep along the east side of the said bridge." This has been suggested as one possible origin for the practice of traffic in Britain driving on the left.[20]

From 1758 to 1762, all houses and shops on the bridge were demolished through Act of Parliament. The two centre arches were replaced by a single wider span to improve navigation on the river.

By the end of the 18th century, it was apparent that the old London Bridge — by then over 600 years old — needed to be replaced. It was narrow and decrepit, and blocked river traffic. In 1799, a competition for designs to replace the old bridge was held. Entrants included Thomas Telford, whose proposal of a single iron arch spanning 600 feet (180 m) was rejected as unfeasible and impractical. John Rennie won the competition with a more conventional design of five stone arches. It was built 100 feet (30 m) west (upstream) of the original site by Jolliffe and Banks of Merstham, Surrey,[21] under the supervision of Rennie's son. Work began in 1824 and the foundation stone was laid, in the southern coffer dam, on 15 June 1825.[citation needed]

The old bridge continued in use while the new bridge was being built, and was demolished after the latter opened in 1831. New approach roads had to be built, which cost three times as much as the bridge itself. The total costs, around £2.5 million (£205 million in 2015),[22] were shared by the British Government and the Corporation of London.

Rennie's bridge was 928 feet (283 m) long and 49 feet (15 m) wide, constructed from Haytor granite. The official opening took place on 1 August 1831; King William IV and Queen Adelaide attended a banquet in a pavilion erected on the bridge.

In 1896 the bridge was the busiest point in London, and one of its most congested; 8,000 pedestrians and 900 vehicles crossed every hour.[1] It was widened by 13 feet (4.0 m), using granite corbels.[23] Subsequent surveys showed that the bridge was sinking an inch (about 2.5 cm) every eight years, and by 1924 the east side had sunk some three to four inches (about 9 cm) lower than the west side. The bridge would have to be removed and replaced.

In 1967, the Common Council of the City of London placed the bridge on the market and began to look for potential buyers. Council member Ivan Luckin had put forward the idea of selling the bridge, and recalled: "They all thought I was completely crazy when I suggested we should sell London Bridge when it needed replacing." On 18 April 1968, Rennie's bridge was sold to an American. It was purchased by the Missourian entrepreneur Robert P. McCulloch of McCulloch Oil for US$2,460,000. The claim that McCulloch believed mistakenly that he was buying the more impressive Tower Bridge was denied by Luckin in a newspaper interview.[24] As the bridge was taken apart, each piece was meticulously numbered. The blocks were then shipped overseas through the Panama Canal to California and trucked from Long Beach to Arizona. The bridge was reconstructed by Sundt Construction at Lake Havasu City, Arizona, and re-dedicated on 10 October 1971. The reconstruction of Rennie's London Bridge spans the Bridgewater Channel canal that leads from the Uptown area of Lake Havasu City and follows McCulloch Boulevard onto an island that has yet to be named.

The London Bridge that was rebuilt at Lake Havasu City consists of a frame with stones from Rennie's London Bridge used as cladding. The cladding stones used are 150 to 200 millimetres (6 to 8 inches) thick. Some of the stones from the bridge were left behind at Merrivale Quarry at Princetown in Devon.[25] When Merrivale Quarry was abandoned and flooded in 2003, some of the remaining stones were sold in an online auction.[26]

The current London Bridge, pictured in January 1987. The skyscraper in the background is the National Westminster Tower, opened six years prior.

The current London Bridge was designed by architect Lord Holford and engineers Mott, Hay and Anderson.[27] It was constructed by contractors John Mowlem and Co from 1967 to 1972,[27] and opened by Queen Elizabeth II on 17 March 1973.[28] It comprises three spans of prestressed-concretebox girders, a total of 928 feet (283 m) long. The cost of £4 million (£51 million in 2015),[22] was met entirely by the Bridge House Estates charity. The current bridge was built in the same location as Rennie's bridge, with the previous bridge remaining in use while the first two girders were constructed upstream and downstream. Traffic was then transferred onto the two new girders, and the previous bridge demolished to allow the final two central girders to be added.[29]

In 1984, the British warship HMS Jupiter collided with London Bridge, causing significant damage to both ship and bridge.

On Remembrance Day 2004, several bridges in London were furnished with red lighting as part of a night-time flight along the river by wartime aircraft. London Bridge was the one bridge not subsequently stripped of the illuminations, which are regularly switched on at night.

The current London Bridge is often shown in films, news and documentaries showing the throng of commuters journeying to work into the City from London Bridge Station (south to north). A recent example of this is actor Hugh Grant crossing the bridge north to south during the morning rush hour, in the 2002 film About a Boy.

On Saturday, 11 July 2009, as part of the annual Lord Mayor's charity Appeal and to mark the 800th anniversary of Old London Bridge's completion in the reign of King John, the Lord Mayor and Freemen of the City drove a flock of sheep across the bridge, supposedly by ancient right.[30]

Rennie's Old London Bridge is a prominent landmark in T.S. Eliot's masterpiece "The Waste Land", wherein he compares the shuffling commuters across London Bridge to the hell-bound souls of Dante's Limbo.

Gary P. Nunn's song "London Homesick Blues" includes the lyrics, "Even London Bridge has fallen down, and moved to Arizona, now I know why." [31]

^The site of the new bridge determined the location of London itself. The alignment of Watling Street with the ford at Westminster (crossed via Thorney Island) is basis for a mooted earlier Roman "London", sited in the vicinity of Park Lane. See Margary, Ivan D., Roman Roads in Britain, Vol. 1, South of the Foss Way - Bristol Channel, Phoenix House Lts, London, 1955, pp. 46 - 47.